Monday, October 9, 2017

Convert MBR System Disk to GPT for Free! - Windows 10 - 1703

We had an issue recently where the solution was to convert the system disk from MBR to GPT. We didn't want to rebuild the computer, and didn't want to pay for some of the commercial tools out there. The fix as it turns out is built into Windows 10 (1703).

To convert the disk, Microsoft has made a little command line tool called mbr2gpt.

To use it is simple:

  1. Boot into Windows Recovery
    1. Select the Start  button, then choose Settings
    2. Select Update & security  > Recovery.
    3. Under Advanced startup select Restart now.
    4. After your PC restarts to the Choose an option screen, select Troubleshoot > Advanced options> Command Prompt
  2. Confirm the disk number you want to work on. If you only have one disk, it should be Disk 0
    1. Type "diskpart" to start the DiskPart Tool
    2. Type "list disk" to view the disks.
    3. Type "Exit" after you determine which Disk you want to edit. In this case, Disk 1 contains my Windows installation.
  3. run "mbr2gpt /convert /disk:X" (Replace X with your disk number)
  4. When it completes, your System disk will be converted to GPT. Make sure you make the appropriate BIOS/UEFI changes to allow you to boot to UEFI instead of Legacy.